1. Field of the Invention
The field of the present invention is central processing units (CPU) for computing devices.
2. Background
A typical computing device, whether it is a personal computer, an embedded computer, a hand-held PDA, a smart phone, or any other type, runs an operating system that is responsible for managing the hardware and various applications. Because of numerous vulnerabilities inherent in today's operating systems and applications, typical computing devices are susceptible to malicious code, such as viruses and spyware. In general, there are two kinds of malicious code.
One kind of malicious code attacks executable files or saves itself on a storage device so it can be resident on the computing device and can spread to other computing devices, usually over a network. This kind of malicious code can usually reload itself to the computing device's memory when the computing device is booted. There are numerous methods to deal with this kind of malicious code, such as anti-virus or anti-spyware programs.
The other kind of malicious code is only resident in the memory of a computing device. This kind of malicious code (memory-resident code) is usually very small in size, often gains administrative privileges, and usually cannot be detected and removed easily as it mimics itself with the operating system.
Regardless of the kind, the malicious code active in the memory may be eliminated by rebooting the computing device. As long as the operating system files and applications are obtained from a clean source (i.e. the operating system files and applications stored in a hard disk are not altered by malicious codes, such as viruses or spyware), a reboot will get rid of any malicious code in the memory.
However, rebooting a computing device usually takes time—from a few seconds for simple devices to several minutes for the more complex devices. While rebooting, the computing device is not operational. This is a major issue when the computing device (i.e. mission critical system, smart phone, etc.), needs to be running almost constantly and cannot have much, if any, downtime